Temperature Dependence of Limiting Activity Coefficients, Henry's Law Constants, and Related Infinite Dilution Properties of Branched (C3 and C4) Alkanols in Water. Measurement, Critical Compilation, Correlation, and Recommended Data

Abstract

Limiting activity coefficients (γ 1 ∞ ) of lower branched alkanols (2-propanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol) in water were measured at several temperatures covering the range from the melting to the normal boiling point of water. Four experimental techniques (namely, headspace analysis, inert gas stripping, Rayleigh distillation, and the method of circulation still) were employed for the purpose. A comprehensive review is further presented of experimental data on the limiting activity coefficients (γ 1 ∞ ), infinite dilution partial molar excess enthalpies (H h 1 E,∞ ), and heat capacities (C h p,1 E,∞ ) of these aqueous solutes. For each alkanol, the compiled data were critically evaluated and together with the data measured in this work correlated with a suitable model equation providing adequate simultaneous description of the equilibrium measurements and the calorimetric information. As a result, a recommended thermodynamically consistent temperature dependence of γ 1 ∞ , H h 1 E,∞ , and C h p,1 E,∞ of superior accuracy was established in the range from the melting point to the normal boiling point of water. In addition, by employing literature data on the respective residual properties of the pure alkanols, analogous recommendations were derived also for the temperature dependence of the Henry's law constants, hydration enthalpies, and hydration heat capacities. Variation of these various infinite dilution thermodynamic properties of aqueous branched alkanols with temperature and alkanol branching is briefly discussed.

Temperature Dependence of Limiting Activity Coefficients, Henry’s Law Constants, and Related Infinite Dilution Properties of Branched Pentanols in Water. Measurement, Critical Compilation, Correlation, and Recommended Data

“…Note that analogous measurements by these authors done for (C3 and C4) branched alkanols have also been found to be substantially in error. 2 Further data belonging to those grossly deviating result from the IGS measurements of Carelli et al 26 (2-methyl-1-butanol, 308.32 K), the HSA measurements of Dallas and Carr 30 (3-methyl-1-butanol), the CIRC measurements of Zou and Prausnitz 20 (2-pentanol, 343.15 K), and the tensimetric measurements of Fischer et al 33 (2-methyl-2-butanol, except for 343.25 K). Apart from the outliers mentioned, most other data are in a good accord supporting the stability of the recommended fit.…”

“…Recently, we have presented results for the temperature dependence of limiting activity coefficients (γ 1 ∞ ) and Henry's law constants (K H ) of (C1 to C5) 1-alkanols 1 and (C3 and C4) branched alkanols. 2 As a logical continuation, we focus here further on branched pentanols. These substances belong to important chemicals with many industrial applications, serving in particular as extraction solvents, reaction media, and precursors to agrochemicals, pharmaceuticals, flavorings, liquid crystals, and dyes.…”

Mapping Hydration Water around Alcohol Chains by THz Calorimetry

“…[4] Experimentally,d ifferential and titration scanning calorimetry gives access to macroscopic changes in heat capacity C p upon phase transitions [1] or upon solvation under equilibrium conditions. [2,3] Here,w ei ntroduce THz calorimetry,wherein local changes of the hydration water are detected via their spectral fingerprints in the THz spectrum. These spectral changes can be linked to local heat capacities and thus local thermodynamics.T he bridge between space-resolved solvent dynamics and space-resolved thermodynamics is evident, since under ambient, physiolog-ically relevant conditions,9 0% of the states contributing to the total entropy of the protein solvent mixture are modes within the frequencyrange between 0and 10 THz (300 cm À1 ).…”

Prediction of gas to water partition coefficients from 273 to 373K using predicted enthalpies and heat capacities of hydration

“…We give in Table 1 values of C p w for 321 compounds, mostly taken either from the old compilation of Cabani et al [10] or from the more recent very important series of papers by Plyasunov and coworkers [6,[11][12][13][14][15][16], or from Fenclova et al [17],Čensky et al [18] and Fujisawa et al [19]. Application of the Abraham equations leads to: In Eqs.…”